GPU hangs are most often from to a high overclock, especially on the memory or too much undervolt for that card. Sometimes draining all the power from the capacitors also helps reset the GPU's and risers after a crash. Shutdown down the rig, cutoff the power to the PSU with the switch on the back and press the power button to drain all the power. Then after 1-2 minutes turn the rig back on.
yep. this can be healthy and helpful sometimes. you don't need to wait 1 minute though:)
As for the 32MH - I'd guess it's rx*80 Polaris, so you should expect it to be unstable at this rate
in any case just as undervolt could cause it the stock voltages could be also too much for the card to handle, so just start from lower mem overclock